SVN r8568
This commit is contained in:
Jordan Sherer
@@ -1,187 +0,0 @@
|
||||
subroutine genmsk144(msg0,mygrid,ichk,bcontest,msgsent,i4tone,itype)
|
||||
! s8 + 48bits + s8 + 80 bits = 144 bits (72ms message duration)
|
||||
!
|
||||
! Encode an MSK144 message
|
||||
! Input:
|
||||
! - msg0 requested message to be transmitted
|
||||
! - ichk if ichk=1, return only msgsent
|
||||
! if ichk.ge.10000, set imsg=ichk-10000 for short msg
|
||||
! - msgsent message as it will be decoded
|
||||
! - i4tone array of audio tone values, 0 or 1
|
||||
! - itype message type
|
||||
! 1 = standard message "Call_1 Call_2 Grid/Rpt"
|
||||
! 2 = type 1 prefix
|
||||
! 3 = type 1 suffix
|
||||
! 4 = type 2 prefix
|
||||
! 5 = type 2 suffix
|
||||
! 6 = free text (up to 13 characters)
|
||||
! 7 = short message "<Call_1 Call2> Rpt"
|
||||
|
||||
use iso_c_binding, only: c_loc,c_size_t
|
||||
use packjt
|
||||
use hashing
|
||||
character*22 msg0
|
||||
character*22 message !Message to be generated
|
||||
character*22 msgsent !Message as it will be received
|
||||
character*6 mygrid,g1,g2,g3,g4
|
||||
integer*4 i4Msg6BitWords(13) !72-bit message as 6-bit words
|
||||
integer*4 i4tone(144) !
|
||||
integer*1, target:: i1Msg8BitBytes(10) !80 bits represented in 10 bytes
|
||||
integer*1 codeword(128) !Encoded bits before re-ordering
|
||||
integer*1 msgbits(80) !72-bit message + 8-bit hash
|
||||
integer*1 bitseq(144) !Tone #s, data and sync (values 0-1)
|
||||
integer*1 i1hash(4)
|
||||
integer*1 s8(8)
|
||||
logical*1 bcontest
|
||||
real*8 pp(12)
|
||||
real*8 xi(864),xq(864),pi,twopi
|
||||
data s8/0,1,1,1,0,0,1,0/
|
||||
equivalence (ihash,i1hash)
|
||||
logical first,isgrid
|
||||
data first/.true./
|
||||
save
|
||||
|
||||
if( first ) then
|
||||
first=.false.
|
||||
nsym=128
|
||||
pi=4.*atan(1.0)
|
||||
twopi=8.*atan(1.0)
|
||||
do i=1,12
|
||||
pp(i)=sin( (i-1)*pi/12 )
|
||||
enddo
|
||||
endif
|
||||
|
||||
if(msg0(1:1).eq.'@') then !Generate a fixed tone
|
||||
read(msg0(2:5),*,end=1,err=1) nfreq !at specified frequency
|
||||
go to 2
|
||||
1 nfreq=1000
|
||||
2 i4tone(1)=nfreq
|
||||
else
|
||||
message=msg0
|
||||
do i=1,22
|
||||
if(ichar(message(i:i)).eq.0) then
|
||||
message(i:)=' '
|
||||
exit
|
||||
endif
|
||||
enddo
|
||||
|
||||
do i=1,22 !Strip leading blanks
|
||||
if(message(1:1).ne.' ') exit
|
||||
message=message(i+1:)
|
||||
enddo
|
||||
|
||||
if(message(1:1).eq.'<') then
|
||||
call genmsk40(message,msgsent,ichk,i4tone,itype)
|
||||
if(itype.lt.0) go to 999
|
||||
i4tone(41)=-40
|
||||
go to 999
|
||||
endif
|
||||
|
||||
if(bcontest) then
|
||||
i0=index(message,' R ') + 3 !Check for ' R ' in message
|
||||
g1=message(i0:i0+3)//' '
|
||||
if(isgrid(g1)) then !Check for ' R grid'
|
||||
call grid2deg(g1,dlong,dlat)
|
||||
dlong=dlong+180.0
|
||||
if(dlong.gt.180.0) dlong=dlong-360.0
|
||||
dlat=-dlat
|
||||
call deg2grid(dlong,dlat,g2) !g2=antipodes grid
|
||||
message=message(1:i0-3)//g2(1:4) !Send message with g2
|
||||
endif
|
||||
endif
|
||||
|
||||
call packmsg(message,i4Msg6BitWords,itype) !Pack into 12 6-bit bytes
|
||||
call unpackmsg(i4Msg6BitWords,msgsent) !Unpack to get msgsent
|
||||
|
||||
if(bcontest) then
|
||||
i1=index(msgsent(8:22),' ') + 8
|
||||
g3=msgsent(i1:i1+3)//' '
|
||||
if(isgrid(g3)) then
|
||||
call azdist(mygrid,g3,0.d0,nAz,nEl,nDmiles,nDkm,nHotAz,nHotABetter)
|
||||
if(ndkm.gt.10000) then
|
||||
call grid2deg(g3,dlong,dlat)
|
||||
dlong=dlong+180.0
|
||||
if(dlong.gt.180.0) dlong=dlong-360.0
|
||||
dlat=-dlat
|
||||
call deg2grid(dlong,dlat,g4)
|
||||
msgsent=msgsent(1:i1-1)//'R '//g4(1:4)
|
||||
endif
|
||||
endif
|
||||
endif
|
||||
|
||||
if(ichk.eq.1) go to 999
|
||||
i4=0
|
||||
ik=0
|
||||
im=0
|
||||
do i=1,12
|
||||
nn=i4Msg6BitWords(i)
|
||||
do j=1, 6
|
||||
ik=ik+1
|
||||
i4=i4+i4+iand(1,ishft(nn,j-6))
|
||||
i4=iand(i4,255)
|
||||
if(ik.eq.8) then
|
||||
im=im+1
|
||||
i1Msg8BitBytes(im)=i4
|
||||
ik=0
|
||||
endif
|
||||
enddo
|
||||
enddo
|
||||
|
||||
ihash=nhash(c_loc(i1Msg8BitBytes),int(9,c_size_t),146)
|
||||
ihash=2*iand(ihash,32767) !Generate the 8-bit hash
|
||||
i1Msg8BitBytes(10)=i1hash(1) !CRC to byte 10
|
||||
|
||||
mbit=0
|
||||
do i=1, 10
|
||||
i1=i1Msg8BitBytes(i)
|
||||
do ibit=1,8
|
||||
mbit=mbit+1
|
||||
msgbits(mbit)=iand(1,ishft(i1,ibit-8))
|
||||
enddo
|
||||
enddo
|
||||
|
||||
call encode_msk144(msgbits,codeword)
|
||||
|
||||
!Create 144-bit channel vector:
|
||||
!8-bit sync word + 48 bits + 8-bit sync word + 80 bits
|
||||
bitseq=0
|
||||
bitseq(1:8)=s8
|
||||
bitseq(9:56)=codeword(1:48)
|
||||
bitseq(57:64)=s8
|
||||
bitseq(65:144)=codeword(49:128)
|
||||
bitseq=2*bitseq-1
|
||||
|
||||
xq(1:6)=bitseq(1)*pp(7:12) !first bit is mapped to 1st half-symbol on q
|
||||
do i=1,71
|
||||
is=(i-1)*12+7
|
||||
xq(is:is+11)=bitseq(2*i+1)*pp
|
||||
enddo
|
||||
xq(864-5:864)=bitseq(1)*pp(1:6) !last half symbol
|
||||
do i=1,72
|
||||
is=(i-1)*12+1
|
||||
xi(is:is+11)=bitseq(2*i)*pp
|
||||
enddo
|
||||
! Map I and Q to tones.
|
||||
i4tone=0
|
||||
do i=1,72
|
||||
i4tone(2*i-1)=(bitseq(2*i)*bitseq(2*i-1)+1)/2;
|
||||
i4tone(2*i)=-(bitseq(2*i)*bitseq(mod(2*i,144)+1)-1)/2;
|
||||
enddo
|
||||
endif
|
||||
|
||||
! Flip polarity
|
||||
i4tone=-i4tone+1
|
||||
|
||||
999 return
|
||||
end subroutine genmsk144
|
||||
|
||||
logical function isgrid(g1)
|
||||
|
||||
character*4 g1
|
||||
|
||||
isgrid=g1(1:1).ge.'A' .and. g1(1:1).le.'R' .and. g1(2:2).ge.'A' .and. &
|
||||
g1(2:2).le.'R' .and. g1(3:3).ge.'0' .and. g1(3:3).le.'9' .and. &
|
||||
g1(4:4).ge.'0' .and. g1(4:4).le.'9'
|
||||
|
||||
return
|
||||
end function isgrid
|
||||
@@ -1,106 +0,0 @@
|
||||
=== AP Decoding
|
||||
|
||||
With the QRA64 decoder Nico Palermo, IV3NWV, introduced a technique
|
||||
for decoding with the aid of information that naturally accumulates
|
||||
during a minimal QSO. This _a priori_ (AP) information can be
|
||||
used to increase the sensitivity of the decoder.
|
||||
|
||||
When an operator decides to answer a CQ, he already knows his own
|
||||
callsign and that of his potential QSO partner. He therefore knows
|
||||
what to expect for at least 56 of the 72 message bits in a
|
||||
standard-format response to his call. The _WSJT-X_ decoders for QRA64
|
||||
and FT8 can use these and similar AP bits to decode messages
|
||||
containing them with higher sensitivity than otherwise possible.
|
||||
|
||||
We have implemented AP decoding in slightly different ways in QRA64
|
||||
and FT8. To provide some explicit examples for users, we provide here
|
||||
a brief description of the FT8 behavior.
|
||||
|
||||
AP decoding attempts effectively set the AP bits to the hypothesized
|
||||
values, as if they had been received correctly. The decoder then
|
||||
proceeds to determine whether the remaining message and parity bits
|
||||
are consistent with the hypothesized AP bits. If a codeword is found
|
||||
that the decoder judges to have high (but not overwhelmingly high)
|
||||
probability of being correct, a ? character is appended when the
|
||||
decoded message is displayed. To avoid misleading spots of occasional
|
||||
false decodes, messages so marked are not forwarded to {pskreporter}.
|
||||
|
||||
Successful AP decodes are always labeled with an end-of-line indicator
|
||||
of the form aP, where P is one of the single-digit AP decoding types
|
||||
listed in Table 1. For example, an `a2` designator says that the
|
||||
successful decode used MyCall as hypothetically known information.
|
||||
|
||||
[[AP_INFO_TABLE]]
|
||||
.AP information types
|
||||
[width="35%",cols="h10,<m20",frame=topbot,options="header"]
|
||||
|===============================================
|
||||
|P | Message components
|
||||
|1 | CQ     ?     ?
|
||||
|2 | MyCall     ?     ?
|
||||
|3 | MyCall DxCall     ?
|
||||
|4 | MyCall DxCall RRR
|
||||
|5 | MyCall DxCall 73
|
||||
|6 | MyCall DxCall RR73
|
||||
|===============================================
|
||||
|
||||
Table 2 lists the six possible QSO states that are tracked by the
|
||||
WSJT-X auto-sequencer, along with the type of AP decoding that would
|
||||
be attempted in each state.
|
||||
|
||||
[[AP_DECODING_TYPES_TABLE]]
|
||||
.AP decoding types for each QSO state
|
||||
[width="35%",cols="h10,<m20",frame=topbot,options="header"]
|
||||
|===========================================
|
||||
|State |AP type
|
||||
|CALLING | 1, 2
|
||||
|REPLYING | 2, 3
|
||||
|REPORT | 2, 3
|
||||
|ROGER_REPORT | 3, 4, 5, 6
|
||||
|ROGERS | 3, 4, 5, 6
|
||||
|SIGNOFF | 3, 1, 2
|
||||
|===========================================
|
||||
|
||||
|
||||
=== Decoded Lines
|
||||
|
||||
Displayed information accompanying decoded messages generally includes UTC,
|
||||
signal-to-noise ratio in dB, time offset DT in seconds, and
|
||||
audio frequency in Hz. Some modes include additional information such
|
||||
as frequency offset from nominal (DF), frequency drift (Drift or F1),
|
||||
or distance (km or mi).
|
||||
|
||||
There may also be some cryptic characters with special meanings
|
||||
summarized in the following Table:
|
||||
|
||||
[[DECODED_LINES_TABLE]]
|
||||
.Notations used on decoded text lines
|
||||
[width="50%",cols="h,3*^",frame=topbot,options="header"]
|
||||
|===========================================
|
||||
|Mode |Mode character|Sync character|End of line information
|
||||
|FT8 | ~ | | ?   aP
|
||||
|JT4 | $ | *, # | f, fN, dNC
|
||||
|JT9 | @ | |
|
||||
|JT65 | # | |
|
||||
|JT65 VHF| # | *, # | f, fN, dNC
|
||||
|QRA64 | : | * | R
|
||||
|ISCAT | | * | M N C T
|
||||
|MSK144 | & | | N H E
|
||||
|===========================================
|
||||
Sync character::
|
||||
`*` - Normal sync +
|
||||
`#` - Alternate sync
|
||||
|
||||
End of line information::
|
||||
`?` - Decoded with lower confidence +
|
||||
`a` - Decoded with aid of some a priori (AP) information +
|
||||
`C` - Confidence indicator [ISCAT and Deep Search; (0-9,*)] +
|
||||
`d` - Deep Search algorithm +
|
||||
`E` - Size of MSK eye diagram opening - if negative, the eye is closed +
|
||||
`f` - Franke-Taylor or Fano algorithm +
|
||||
`H` - Number of bit errors corrected +
|
||||
`M` - Message length (characters) +
|
||||
`N` - Number of Rx intervals or frames averaged +
|
||||
`P` - Number indicating type of AP information (Table 1, above) +
|
||||
`R` - Return code from QRA64 decoder +
|
||||
`T` - Length of analyzed region (s)
|
||||
|
||||
Reference in New Issue
Block a user